1. Field of the Invention
The present invention relates to a protective plug for a distributor strip utilized in telecommunications systems, particularly in telephone private branch exchanges (PBXs), the protective plug containing a surge arrester whose wire-like terminal elements are connected to contact elements that are, in turn, connectible to cooperating contacts of the distributor strip after being plugged on, whereby the service side of the distributor strip comprises a plurality of terminal posts in the longitudinal direction that enable a stripping-free connection of electrical conductors.
2. Description of the Prior Art
Such cooperating contacts are usually connected to contact parts that form the contact assigned to a line in the distributor strip. The German published application 30 14 796 discloses such a protective plug that can be provided with plug tongues that can be plugged into a plug connector strip, whereby a connection between the plug tongues and the spring contacts connected to the electrical lines is produced. The protective plug is provided with surge arresters which are connected to the plug tongues. The other pole of the surge arrester is connected to a grounding rail. The protective plug comprises a plurality of receptacle chambers into which a respective surge arrester is introduced. When the protective plug is pulled, a plurality of lines of the distributor strip are without over voltage protection.
The German Letters Patent DE 38 13 889 C1, for example, has disclosed that separate protective plugs be assigned to individual line leads. The surge arrester belonging to a line lead comprises no terminal legs but is directly held with its contact locations by contact springs. These contact springs are in turn in communication with a plug-in part. The housing of the pluggable protective plug, the housing being open at one side, is closed by the plug-in tongue belonging to a grounding rail. At the same time, the electrically-conductive connection is produced from the one terminal contact location of the surge arrester to the grounding rail.
Compared to the inherently-known possibilities of providing what are referred to as protective strips or rails for the connection of the surge arresters, the utilization of such protective plugs has the advantage that no additional jumpering measures are required and that the space required for such additional protective strips is saved. A possibility for protection is optionally given with such strips even through only a relatively small portion of the subscriber lines, for example, are to be protected.